Convert Julian Years to Synodic Months
Convert Julian Years (a_J) to Synodic Months (syn.mo) instantly and accurately.
Conversion Formula
syn.mo = a_J × 12.36853088
About Julian Years
The Julian year (a_J) = exactly 365.25 days = 31,557,600 s - the IAU standard year for astronomical distances. The light-year is formally 1 ly = c × 1 a_J = 9.461 × 10¹⁵ m (IAU 2012 B2). Julian years differ from Gregorian years by only 648 s (~10.8 min/year); important for high-precision astrometry or calculations spanning centuries. 1 a_J = 365.25 d = 31,557,600 s.
About Synodic Months
A synodic (lunar) month = new moon to new moon = 29.5306 days = 2,551,442.9 s. Longer than the sidereal month (27.32 d) because Earth advances ~27° in its orbit during that time; the Moon must travel further to realign with the Sun. Islamic Hijri, Hebrew lunisolar, and Chinese calendars are built on synodic months. Eclipses repeat via the Saros cycle (18 yr 11 d = 223 synodic months). 1 syn.mo ≈ 29.5306 d.
Quick Reference Table
| Julian Years (a_J) | Synodic Months (syn.mo) |
|---|---|
| 1 a_J | 12.3685 syn.mo |
| 2 a_J | 24.7371 syn.mo |
| 5 a_J | 61.8427 syn.mo |
| 10 a_J | 123.685 syn.mo |
| 25 a_J | 309.213 syn.mo |
| 50 a_J | 618.427 syn.mo |
| 100 a_J | 1236.85 syn.mo |